1. Field of the Invention
The present invention relates to a liquid jet recording head for discharging a liquid such as a recording liquid and the like from discharge ports and forming liquid droplets and to a recording apparatus including the liquid jet recording head.
2. Related Background Art
A recording apparatus having a function as a printer, copy machine, facsimile and the like, or a recording apparatus used as an output device of composite type electronic equipment including a computer, word processor, and the like and used as an output device of a workstation is arranged to record information such as an image and the like on a recording medium such as a recording sheet, plastic thin sheet and the like based on recording information. This type of the recording apparatus can be classified into an ink jet system, wire dot system, thermal system, laser beam system and the like.
FIG. 16 shows a perspective view of an outside appearance of a conventional liquid jet recording head, and FIG. 17 shows an exploded perspective view of a conventional liquid jet recording head.
As shown in FIGS. 16 and 17, the conventional liquid jet recording head includes recording element substrates 201 for discharging liquid droplets, a support substrate 202 for supporting the recording element substrate 201, wiring sheets 203 and a terminal wiring substrate 205 for supplying a recording signal to the recording element substrates 201, and a flow path-forming member 206 having a flow path for supplying a recording liquid to the recording element substrates 201.
In the recording apparatus described above, the recording liquid may be attached in a wet state to a recording liquid discharge surface, on which discharge ports are disposed, due to mists, satellites (a part of liquid droplets separated from discharged liquid droplets), and the like generated when the recording liquid is discharged from the liquid jet recording head. Further, in a recover process for sucking the recording liquid remaining in the discharge ports therefrom, and the like, the recording liquid which is not sucked and remains may be attached on the recording liquid discharge surface.
To cope with the above problem, the conventional recording apparatus includes a recovery unit for removing the recording liquid adhered to and remaining on the recording liquid discharge surface. The recovery unit is mainly composed of a suction mechanism for forcibly discharging the recording liquid by sucking it from the discharge ports of the recording liquid discharge surface and a wiping mechanism for cleaning the recording liquid discharge surface by wiping the recording liquid therefrom.
The wiping mechanism has a blade composed of, for example, an elastic member and the like and cleans a plurality of the discharge ports and the periphery thereof in such a manner that the distal end of the blade is directly abutted against the recording liquid discharge surface of the liquid jet recording head and is caused to be in sliding contact with the discharge surface while it is moved relatively with respect to the discharge surface, thereby the stability of a discharging operation can be secured.
An example of the recovery unit will be described below with reference to the drawings. FIG. 18 shows a perspective view of a recording apparatus having the recovery unit, and FIG. 19 shows a schematic side elevational view of a wiping operation executed by the recovery unit. As shown in FIG. 18, a liquid jet recording head 301 is mounted on a carriage 302, discharges the recording liquid from the discharge ports of a recording liquid discharge surface 301a, and records information such as an image and the like on a recording medium 305. The carriage 302 is supported by a guide shaft 303 for guiding a moving direction thereof and moves reciprocally in confrontation with the recording medium 305. The recording medium 305 is caused to come into pressure contact with a feed roller (not shown) by a pinch roller (not shown) and is transported by the feed roller being rotated.
Further, the recording medium 305 on which desired information has been recorded is discharged to the outside of the recording apparatus by a discharge roller (not shown). Then, dust such as paper powder and the like adhered to the recording liquid discharge surface 301a and the recording liquid remaining thereon are scraped by a blade 304 disposed to the outside of a recording region (wiping mechanism). In addition, a cap 306 is provided to prevent the clogging of the discharge ports, which is caused when the recording liquid adhered thereto is dried, by covering the recording liquid discharge surface 301a and to suck the recording liquid from the outside of the liquid jet recording head (suction mechanism). Here, a conventional method of an operation (wiping operation) for cleaning the recording liquid discharge surface 301a by scraping the dust and the recording liquid thereon by the blade 304 will be described.
In FIG. 19, reference numerals P1, P2, and P3 show respective states of of the blade 304, that is, commencement of the wiping operation, during the wiping operation, and after termination of the wiping operation.
When the blade 304 is moved by the wiping mechanism in the direction of an arrow V in FIG. 19, it comes into sliding contact with and moves on the recording liquid discharge surface of the liquid jet recording head 301. That is, when the wiping operation starts, the distal end of the blade 304 is subjected to the sliding resistance of a side surface of the liquid jet recording head 301, is elastically deformed in a curved state, and comes into press-contact with the recording liquid discharge surface 301a. Since the liquid jet recording head 301 is further moved in the press-contact state, the dust and the recording liquid adhered onto the surface of the recording liquid discharge surface 301a is scraped with the distal end of the blade 304. Thus, when the liquid jet recording head 301 has entirely passed through the blade 304, the original upright state of the blade 304 is elastically restored.
As described above, the wiping mechanism cleans the recording liquid discharge surface 301a through a series of the wiping operation executed by the blade 304, thereby the discharging operation of the recording liquid can be stabilized, and an excellent recorded image and the like can be obtained.
When the wiping operation is carried out, the periphery of the discharge ports is sufficiently cleaned. However, a problem is arisen in that the recording liquid deposits on the side from which the blade 304 comes onto the recording liquid discharge surface 301a. 
In other words, repetition of the wiping operation causes the wiped recording liquid to deposit on the distal end of the blade 304. Accordingly, when the blade 304 comes onto the recording liquid discharge surface 301a next, the recording liquid deposited on the distal end of the blade 304 is transferred to and deposited on the side surface of the recording liquid discharge surface 301a from which the blade 304 comes onto the recording liquid discharge surface 301a. Moreover, the deposited recording liquid is dragged by the blade 304 and rubbed onto the recording liquid discharge surface 301a. 
Further, there is a possibility that the recording liquid deposited on the side surface and the like of the recording liquid discharge surface 301a rises from the wiring sheet 203 side to a connection terminal 204 by a capillary action. To prevent the arrival of the remaining recording liquid at the connection terminal 204, the conventional liquid jet recording head employs a countermeasure for preventing the rising of the recording liquid by forming a barrier wall composed of a seal agent, adhesive or the like between the connection terminal 204 and a bent portions 203a of the wiring sheets 203.
In contrast, on a leaving side of the recording liquid discharge surface 301a from which the blade 304 leaves, the blade 304 attempts to return to an upright state by the elastic recovering action thereof after it cleans the recording liquid discharge surface 301a. The blade 304 is excessively oscillated by the recovering action and scatters the collected recording liquid in a mist state in the leaving direction of the blade 304 due to the oscillation.
In general, the wiping mechanism sets a direction in which the wiping operation is carried out to any one of four directions, that is, directions in which the discharge ports as described above are disposed and directions orthogonal to the disposing directions of the discharge ports. However, when the wiping operation is carried out in the directions orthogonal to the disposing directions of the discharge ports, there is a possibility that recording quality is deteriorated because many kinds of recording liquids are mixed with each other by the mists and the like scattered in the wiping operation.
Further, when the blade 304 comes onto the recording liquid discharge surface 301a, the distal end of the blade 304 is caught by side ends 203c of the wiring sheets 203 positioned at the outer periphery of the recording liquid discharge surface 301a. Thus, the blade 304 and the wiring sheets 203 are greatly damaged by the repetition of the wiping operation.
As a countermeasure for solving the above problem, when the blade 304 comes on to the recording liquid discharge surface 301a from the bent portions 203a of the wiring sheets 203 and the wiping operation is carried out in the disposing direction of the discharge ports, the damage of the blade 304 and the wiring sheets 203 as described above can be avoided.
Accordingly, as shown by the direction of the arrow V, a serial type recording apparatus generally employs the wiping operation of the blade 304 in which the blade 304 comes onto the recording liquid discharge surface 301a from the side of the bent portions 203a of the wiring sheets 203, which is an electrically connecting side (from the side of a back surface of the liquid jet recording head), and leaves to the front surface side of the liquid jet recording head (for example, the direction of an arrow S in FIG. 12).
In contrast, particularly in a mailing machine and the like of a line type recording apparatus, since a recording region of a recording medium is disposed forward of a front surface of the liquid jet recording head, mists of the recording liquid and the like produced by the wiping operation must be prevented from scattering to the recording region of the recording medium. Thus, the blade 304 comes onto the recording liquid discharge surface 301a from the front surface of the liquid jet recording head and leaves to an electrically connecting portion of the liquid jet recording head (the back surface of the liquid jet recording head).
However, as shown in FIGS. 16 to 19, when the blade 304 comes onto the recording liquid discharge surface 301a from the front surface of the liquid jet recording head in the conventional recording apparatus, the distal end of the blade 304 is caught by end portions 203b of the wiring sheets 203. Thus, a problem is arisen in that the recording liquid is liable to deposit on stepped portions formed by the end portions 203b of the wiring sheets 203.
Further, in the conventional recording apparatus, there is a possibility that the end portions 203b of the wiring sheets 203 are exfoliated from the support substrate 202 by the repetition of the wiping operation. When the end portions 203b of the wiring sheet 203 are exfoliated even in a slight amount, the wiring sheets 203 are furthermore exfoliated by the wiping operation carried out repeatedly thereafter. Thus, in the conventional recording apparatus, a disadvantage is arisen in that the liquid jet recording head is damaged or cannot be sufficiently cleaned.
To prevent the blade 304 from being caught by the end portions 203b of the wiring sheets 203 by avoiding the above problem, there is contemplated a countermeasure for regulating a region in which the blade 304 comes into sliding contact with the recording liquid discharge surface 301a by reducing the movable range of the blade 304.
However, in the above countermeasure, first, the blade 304 must be advanced to and retracted from the recording liquid discharge surface 301a, which is disadvantageous in that a manufacturing cost of the wiping mechanism is increased. Second, a disadvantage is also arisen in that there is a possibility that dust and dirt (dust, paper powder, paper fluff and the like) and viscosity-increased ink (ink having whose viscosity is increased by the evaporation of a volatile component) which were collected by the blade 304 in the wiping operation are adhered again. That is, since the dust and the viscosity-increased ink collected by the distal end of the blade 304 and adhered thereto in the wiping operation are pressed against and transferred onto the recording liquid discharge surface 301a when the blade 304 advances and retracts, there is a possibility that the viscosity-increased ink is strongly and firmly adhered.
As described above, the countermeasure for regulating the sliding-contact region between the blade 304 and the recording liquid discharge surface 301a is not advantageous.
Further, when liquid jet recording heads having the same specification are mounted on a serial type recording apparatus on one hand and mounted on a line type recording apparatus on the other hand, two types of liquid jet recording heads must be manufactured to cope with wiping directions different from each other. This increases a manufacturing cost of the liquid jet recording heads and deteriorates productivity.